Method of making culverts



1934- J. R. FREEZE ETAL 8 METHOD OF MAKING CULVERTS Original Filed Oct.'7, 1931 INVENTORS,

VQZZ

ATTORNEYS,

Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE i, METHOD OF MAKINGCULVISE'IS application October 7, 1931, Serial No.

567,461. Divided and this application June 2, 1933, Serial No. 674,057

'lClaims.

This application is a division of application Serial No. 567,461 filedOctober 7, 1931.

Our invention relates to the manufacture of corrugated metal culvertshaving erosion and corrosion resisting linings, and to methods of makingthe same.

Corrugatedsteel or iron culverts (usually galevanized) are of greatvalue in the arts because of their great strength and relatively lightweight and small bulk as compared to brick, concrete or tile culverts.When subjected to excessive loads, corrugated metal culverts willdistortin shape to conform best to load conditions. This is not possiblewith concrete or tile culverts,

-.and is no doubt one of the reasons which enable the use of acorrugated metal for culvert purposes. g

The zone of weakness in a metal corrugated culvert is in the invert orlower section of the culvert, particularly along what may be termed thebase thereof. Gravity fiow of water and whatever soil, dirt or abrasivematter it carries, is along the base of a culvert.

In U. 8. Patent No. 1,652,703, dated December 13, 1927,.to Allerton S.Cushman, is shown and described a culvert having a paving oi asphalticmaterial in the basethereof, which forms a level floor along the base ofthe culvert and protects the sides ordinarily by a fairly thin film ofthe bitumen. According to the Cushman patent, asphalt while fluid isplaced into a culvert section which is then held level while the asphalthardens. The asphalt flows to the center of the base line of the culvertand fills the corrugations, forming a pool along the center line. This,when hard, forms a level floor in the culvert. The culvert iseitherdipped into molten bitumen or sprayed internally with it, in the processof manufacture, as a mode of placing the bitumen in the culvert. Whereit is desired to have the corrugations filled, toan extent greater thana single collected pool inv the base of the culvert will do, therewill'haIve to be subsequent dippings or sprayings with the culverttilted slightly at an angle to its position during the first dipping orspraying. y a

This re-dippins or spraying and subsequent hardening is a somewhatcumbersome method of procedure. Also, where a series oi clippings aremade, the more extended corrugationfilling or fioor in the culvert isnot smooth and round, but has one or more angles where the severalcoatings or fillings join.

It is an object oi our invention to provide for a way oi filling thecorrugations of a corrugated culvert to whatever depth and to whateverwidth of sector of the culvert is desired, by a simpler method ofapplication and with enhanced results.

Thus it is our object to make the filling separate.from the culvert andarrange to have it inserted and bound in place later. This has anadvantage in practice, since it avoids the necessity of a series oftreatments by filling, heating and cooling, and requires simplerequipment at the culvert factory.

We have illustrated in the drawing an example of our invention, and willdescribe the same in full. In the claims that follow, we setiorth theessentials making up our invention, and we here refer to the claimswithout further discussion oi possible variations or modifications ofour invention.

In the drawing:'

Figure 1 is .a perspective view oi a piece oi molded culvert filling,showing its shape before it is placed into the culvert.

Figure 2 is a perspective, partly broken away,

metal culvert at 1. At 2 is illustrated a typical filling for theculvert. This is a molded product having a top surface which is smoothand cylindrical, and a bottom surface 3 which is corrugated exactly tocorrespond to the interior corrugations of a culvert into which it is tobe placed. The lateral margins 4 may be tapered so as to avoid anyabrupt shoulder when the lining is inserted in the culvert. The ends oithe sections may be made smooth, to make butt joints with the fillingsof adjoining sections, or may be made specially to establish a differentstyle of joint. As a material for the lining we use preferably a fiberreinforced bituminous compound, which, when cold, is flexible and limp,and will have a shape such as shown in Fig. 1, before it is placed intothe culvert.

In the simplest practice the metal sections are made up at the culvertfactory, and the filling made up at a factory where there is properequipment for making molding compounds and molding them. Whentheculverts are to be lined or filled, the lining is inserted in place,the culvert section heated externally so as to soften the 'contactingsurface of the lining, and the outside of the culvert then cooled orpermitted to cool. The result of the heating will be tobond the liningto the culvert, which will be permanent except for a reheating.

We have also found in actual practice if we place ordinary burlapbetween the interior floor of the culvert and the asphalt lining, abetter bond between the culvert section and insert filling is provided,particularly in cold temperatures, and in addition if the culvertsection is subjected to rough usage before or during installation, theasphalt cake will remain intact and firmly bonded to the culvert. Again,if this burlap layer is attached to the asphalt lining at the factoryand the unit is roughly handled while being shipped or transported tothe place of use, the asphalt cake will remain as a unit and will not bebroken or rendered unfit for use.

The degree of curve in cross section of the lining pieces can be asdesired. If the entire interior of the culvert is to be lined, therewill preferably be two half cylinders or multiple sections of the liningused, depending on the diameter of the culvert.

A simple factory equipment can be used, such as a conveyor, a materialholder to use in inserting the lining and dropping it into place withthe corrugations thereon meshing with those in the culvert, and a heaterover which the conveyor carries the culvert section with lining inplace, and finally, a water spray for chilling the outside of theculvert to prevent dislodgment or slipping of the lining and to savetime in holding the completed article until cooled down in theatmosphere.

Any convenient mode, however, of heating up the culvert section afterthe lining is in place will serve.

The thickness of the filling can be controlled as desired, and tapered01'1" to the sides away from the center with consequent saving ofmaterial where easy conditions of use are to be met.

With a molded top surface, it is evident that the exact type of surface,level, curve, etc., that is desired can be provided.

Our invention should be distinguished from instances where it has beensuggested to mold within a pipe section some filling material, or toinsert within the invert of a pipe section, some level fiow sustainingfioor, which is of metal, ceramic material, or otherwise formed.

As material for the filling pieces, the chief requisites are that theybe heat plastic, of high adhesiveness. and flexible at room temperatureso that it will adapt itself to any particular shape of culvert to belined. The bituminous ingredient should not be short or brittle innature, so as to allow for contraction and expansion, and also fordistortion under load of the culvert in which it is placed.

In order to insure against trapping of air between the lining and theinner culvert wall, it is advisable to rock the culvert in a directioncircumferential of the culvert section, or to shake or jar the culvertwhen his being heated for bonding the lining in place. It isadvantageous to heat the culvert first on its lowestpart, thus allowingany entrapped air to escape up the sides before the bonding takes place.It furthermore is helpful in avoiding entrapment of air if the corrugaetions of the lining are made somewhat higher than would correspond tothe corrugations of the metal culvert.

In spite of the cost of molding, the lining of culverts as we havedescribed, is more economical than the former methods employed, as wellas the product being one of enhanced value and greater accuracy. Theonly heating of the filling material sufiicient to melt it is done priorto molding. The heating of the culvert section is brief, and purposelykept down to just sufiicient to establish a bond with the lining. Thereis no necessity for re-dipping for a second filling.

While our culverts may be dipped after the lining is in place, this isnot necessary. In case dipping. is done, however, the molded liningswill preserve their form better than the linings as provided for in theprocess described in said Cushman patent.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent, is:

1. A method of filling the corrugations of a corrugated sheet metalculvert, which consists in forming the culvert section, molding aheatplastic filling therefor having on its one face corrugations tomatch the corrugations of the culvert section, placing the fillingsection in the culvert in meshing position as to corrugations. andapplying heat to the outside of the culvert sufiicient to melt thecontacting surface of the filling, wherefore it will bond with theculvert interior.

2. A method of filling the corrugations of a corrugated sheet metalculvert, which consists in forming the culvert section, molding a heat-5 plastic filling therefor having on its one face corrugations to matchthe corrugations of the culvert section, placing the filling section inthe culvert in meshing position as to corrugations, and applying heat tothe outside of the culvert sufiicient to melt the contacting surface ofthe filling, wherefore it will bond with the culvert interior, andsubsequently cooling the culvert section, as by a suitable spray.

3.A method of filling the corrugations of a 1 corrugated sheet metalculvert, which consists in forming. the culvert section, molding aheatplastic filling therefor having on its one face corrugations tomatch the corrugations of the culvert section, placing the fillingsection in the culvert in meshing position as to corrugations, andapplying heat to the outside of the culvert sufiicient to melt thecontacting surface of the filling, wherefore it will bond with theculvert interior, and jarring the culvert section during interior, andproducing a reciprocating movement in a circumferential direction of thecul vert section during the heating, for the purpose described.

5. A method of filling the corrugations of a corrugated sheet metalculvert, which consists in forming the culvert section, molding aheatplastic filling therefor having. on its one face corrugations tomatch the corrugations oi the culvert section, attaching burlap to saidfilling, placing the filling section in the culvert in mesh= ingposition as to corrugations, and applying heat to the outside of theculvert sumcient to melt the contacting surface of the filling,wherefore it will bond with the culvert interior.

6. A method of filling the of-a corrugated sheet metal culvert, whichconsists in forming the culvert section, placing burlap on the interiorfioor thereof, molding a heat-plastic 75 the culvert section, separatelymolding a heat filling therefor having on its one face corrugations tomatch the corrugations of the culvert section, placing the fillingsection in the culvert in meshing position as to corrugations, andapplying heat to the outside of the culvert sufficient to melt thecontacting surface of the filling, wherefore it will bond with theculvert interior.

7. A method of producing a paved corrugated sheet metal culvert, whichconsists informing plastic filling therefor having on one of its facescorrugations substantially corresponding to the corrugations of theculvert section, placing the filling in the culvert section in meshingposition as to corrugations, and bonding the filling to the culvertsection.

JONATHAN ROY FREEZE. RALPH W. SHAR'ILE.

